Stand for assembling and pressing magnetic circuits of power transformers

ABSTRACT

A stand comprises an assembly table mounted on a turnable base with said table having supports for cores and yokes of a magnetic circuit and provided with a winding device. The winding device is provided with a separable body embracing the elements of the magnetic circuit to be bandaged. The body accommodates a separable ring rotating about the elements of the magnetic circuit and carrying an axle for receiving a spool with a tape of bandaging material.

United States Patent [191 Pshenichnyet al.

[451 May 28, 1974 l l STAND FOR ASSEMBLING AND PRESSING MAGNETIC CIRCUITS OF POWER TRANSFORMERS [76] Inventors: Gennady Ivanovich Pshenichny,

ulitsa Kremlevskaya, 27, kv. 8; Yakov Zinovievich Checheljuk, Dnepropetrovskoe shosse, 62, kv. 65; Ivan Ivanovich Gryazev, Berezovy pereulok, 3, all of Zaporozhie, USSR.

22] Filed: July 7, 1972 21 Appl. No.: 269,582

52 U.S.Cl 29/203 D, 29/2031.

51 lnt.Cl. H05k 13/00 [58] Field of Search 29/203 D, 203 L, 203 R, 29/2031 [56] References Cited UNITED STATES PATENTS 3,605,235 9/l97l Van Der Horst 29/203 L Primary ExaminerThomas H. Eager Attorney, Agent, or FirmEric H. Waters 57] ABSTRACT A stand comprises an assembly table mounted on a tumable base with said table having supports for cores and yokes of a magnetic circuit and provided with a winding device. The winding device is provided with a separable body embracing the elements of the magnetic circuit to be bandaged. The body accommodates a separable ring rotating about the elements of the magnetic circuit and carrying an axle for receiving a spool with a tape of bandaging material.

4 Claims, 5 Drawing Figures PMENTEDMAY 28 19M SHEET 3 0F 4 F/EJ STAND FOR ASSEMBLING AND PRESSING MAGNETIC CIRCUITS OF POWER TRANSFORMERS This invention relates to technological equipment adapted to be employed in the manufacture of transformers and, more particularly, relates to stands designed for assembling magnetic circuits of power transformers.

It is known that any magnetic circuit comprises a metallic frame made of cores and yokes connecting these cores. The cores are designed for supporting the windings of the transformer and have a generally round cross section.

A magnetic circuit, in accordance with the lamination pattern thereof, is composed of laminations of various width which, in turn, are stacked together from sheets cut out of electrical sheet steel, followed by pressing these stacks and clamping them by means of bandages made of tape-like material such as glass fabric tape, which is then wound around the elements of the magnetic circuit (cores and yokes) as a multilayer bandage. Such multilayer bandages are wound around the elements of the magnetic circuit at predetermined spacings.

Known in the art are stands for assembling magnetic circuits of power transformers, each comprising a turntable base carrying an assembly table having a system of supporting elements on which laminations are placed, thereby forming the elements of the magnetic circuit being assembled.

The pressing of these laminations is performed by means of a removable pressing beam which is mounted above the assembly table on vertical guide bars, the beam being capable of moving along said guide bars.

Shoes are attached to the lower side of the beam above each supporting element of the assembly table, and upon movement'of the pressing beam towards the table, the shoes transmit a force to the laminations which are lying on the supporting elements of the table.

A device for clamping and fixing technological tie clamps to the magnetic circuit elements is provided at the upper portion of the pressing beam, with the device being capable of moving along the beam axis. The clamps are mounted at a given interval which is defined by the bandage spacings.

In such an arrangement, the magnetic circuit being assembled must be removed from the stand and bandaged with multilayer bandages by winding them around the portions of the elements of the magnetic circuit disposed between the tie clamps, followed by removing the tie clamps.

The bandaging operation is carried out by means of a winding machine which is placed upon the magnetic circuit being assembled.

Consequently, the known stand does not provide for complete assembling of magnetic circuits, but only for stacking the magnetic circuit elements with the subsequent pressing and clamping thereof by means of the clamping ties, while the bandaging of the elements of the magnetic circuit being assembled must be continued at another stand. This results in a complication of the assembling procedure and makes it more time consuming and expensive.

Apart from the above disadvantages, the bandaging of the magnetic circuit elements separately of the stand, after relieving the pressing force from the, magnetic circuit, causes a reduction of the magnetic circuit space factor and consequently impairs the overall tcchnical characteristics of the transformers.

It is an object of the present invention to provide a stand designed for assembling magnetic circuits of power transformers which makes it possible to perform the complete assembling of the magnetic circuits, including the operation of bandaging of the elements of magnetic circuits, without the need for relieving the pressing force from the magnetic circuits.

It is another object of the invention to improve the technical characteristics of a transformer by increasing the magnetic circuit space factor.

These and other objects of the invention are accomplished by providing a stand for assembling magnetic circuits of power transformers, comprising a turnable base mounting an assembly table which has supports for the elementsof the magnetic circuit to be assembled, and a removable beam disposed above the assembly table or guide bars which are adapted to move along said guide bars and providing with shoes attached to the lower portion of the beam over each supporting element of the assembly table, and adapted to transmit the pressing force to the magnetic circuit elements placed on the table supports.

According to the invention, the pressing beam is provided with a winding device movable along the beam axis, and has a separable body adapted to embrace the element of the magnetic circuit to be bandaged stepby-step at the portions thereof disposed between the shoes of the pressing beam, while the body accommodates a separable ring which carries an axle adapted to receive a spool with a bandaging tape and is rotated relative to the portion of the magnetic circuit being bandaged for winding the bandaging tape thereabout.

The stand according to the present invention makes it possible to perform all the assembly operations, including the bandaging, on one and the same stand, thereby reducing the time necessary to assemble magnetic circuits by eliminating intermediate timeconsuming operations, such as placing and removing the technological tie clamps, removing magnetic circuits from the stand and mounting them on separate equipment in order to carry out the bandaging operation.

Among other aspects, it is of particular importance, that the bandaging of the magnetic circuit elements, in accordance with the present invention, is performed without relieving the pressing force due to the fact that the winding device is placed directly on the portions disposed between the shoes where the bandages are wound. This makes it possible to increase the magnetic circuit space factor and, therefore, to improve the technical characteristics of power transformers.

It is preferable that the body of the winding device and the ring disposed in the body together with the axle for a spool with the bandaging tape, be separable along a'vertical plane which extends through the axis of the pressing beamand divides the body and the ring into two symmetrical parts which may be brought together or moved apart in a plane extending normal to the axis of the pressing beam.

Such an arrangement makes it possible to shift the parts of the winding device body, together with the parts of the rings accommodatd therein, apart for a distance exceeding the width of the pressing beam shoes 3 in order to pass clear of the shoes during the movement of the winding device along the pressing beam axis to the next portion of the magnetic circuit being bandaged, whereupon the parts of the body and those of the ring are again brought together.

In order to ensure the bringing together of the parts of the body and of the ring or moving them apart, the parts are suspended from associated sliders which are mounted on the pressing beam guide and interconnected by means of a screw drive interlocked with another drive means adapted to shift the winding device along the pressing beam axis.

It is also preferable to make the ring, having the axis for receiving a spool with bandaging material, in the form of a gear adapted to be meshed with another gear which is driven via a chain drive and a reduction gear by an electric motor secured to the pressing beam.

Other objects and advantages of the present inven tion will become more clear from the following detailed description of the preferred embodiment thereof ,with reference to the accompanying drawings, in which:

FIG. 1 is a side elevational view of a stand for assembling magnetic circuits of power transformers, according to the invention;

FIG. 2 is a detail A in FIG. 1 on an enlarged scale (in the vertical position of the stand);

FIG. 3 is a sectional view on an'enlarged scale taken along line IIl--Ill in FIG.'1;

FIG. 4 is a similar sectional view as in FIG. 3, (with the parts of the winding device body in the spaced apart position; and r I FIG. 5 is a fragmentary longitudinal section of a detail B in FIG. 1, shown on alarger scale.

GENERAL DESCRIPTION OF THE STAND STRUCTURE Referring to FIG. 1, the stand of the present invention for assembling magnetic circuits of power transformers comprises a turnable base 1 mounting an as- DETAILED DESCRIPTION OF THE STAND UNITS The turnable base 1 of the stand has a sledge-like structure with two parallel skids l2 interconnected by means of cross beams (not shown in the drawings) and mounted on a plate 13 (FIG. 2) which, in turn, is secured to a foundation 14 of the stand. Fingers 15 are fixed to the internal surface of the curvilinear portion of the sledges 12. Upon turning the sledges 12 of the base 1 into the vertical position, the fingers successively engage tooth racks 16 attached to the plate 13 of the base 1, thereby preventing the sledges 12 from being shifted with respect to the plate 13.

The turning of the stand base 1 (together with the assembly table 2) from the horizontal position into the substantially vertical position is performed for removing the assembled magnetic circuit from the stand in a vertically oriented position in order to prevent demaging thereof.

Supporting brackets 17 are provided in order to fix the base 1 in the vertical (or inclined) position, each supporting bracket being pivotally connected at one end thereof to the internal side of the associated sledge 12, and at the other end thereof abutting against a stop 18 provided on the plate 13.

l A handle 19 is provided on the pivot axis of each bracket 17 outside the sledge 12, the handle being adapted to return the stand base 1 to its original horizontal position.

The assembly table 2 comprises three parallel longitudinal beams 20 (FIG. 1) (according to the number of cores 5 of the magnetic circuit to be assembled) which are mounted on the stand base 1 in such a manner as to adjust the distance therebetween when changing for magnetic circuits of anotherjtype and size. In so doing two side beams 20 are displaced along the cross beam guides 21 and fixed to these guides by means of bolts 22, while the intermediate beam 20 is moved relatively to the side beams by means of a screw (not shown) which is driven by a handwheel 23.

The supports 3 for stacking the core 5 of the magnetic circuitare mounted at the middle of each beam 20 of the table 2, while the supports 4 are placed on the sides of the beam for assembling the yokes 6. Bars with stops 24 are disposed adjacentthe supports 4, these bars being adapted to fix the stacks 25 of laminations (from which the cores and yokes are formed) in the horizontal position.

Secured to the front end faces of the longitudinal beams 20 are brackets 26 with abutment screws, with these brackets preventing the assembled magnetic circuit from slipping off the table 2 when the latter is turned into the vertical position.

Suitable sockets'are provided at the ends of each beam 20 of the assembly'table 2. These sockets receive wedges 28 for securing the lower ends'of the vertical bars 7 carrying the horizontal pressing beam 8, which is removable (together with the bars), and is provided with pressing shoes 29 which are attached to the lower portion of the beam above each respective support 3 of the core 5 of the magnetic circuit being assembled.

Such pairs of the supports 3 and the shoes 29 are spaced along the whole length of the beam at predetermined intervals corresponding to the spaces between the bandages.

The shoes comprise metallic blocks secured to the pressing beam 8 by means of bolts 30 (FIG. 4) and are adapted to transmit the pressing force from the beam 8 to the stacks 25 of laminations forming the core 5 upon movement of the beam 8 towards the assembly table 2. v v I The movement of the pressing beam 8 along the bars 7 is performedby means of the two drives 9 operating synchronously and mounted on the ends of the beam 8.

Each above-mentioned drive 9 comprises an electric motor 31 and a reduction worm gear 32, the worm of which is driven by the shaft 34 of the electric motor 31, while a hub 35 of a worm wheel 36 is provided with a through passage accommodating the threaded end of the bar 7 which is loosely fitted into the passage. A nut 37 is attached to the upper end face of the hub 35, the nut being screwed onto the threaded end of the bar.

The winding device (FIG. 1) is mounted on the pressing beam 8 at the middle portion thereof and is movable along the axis of the pressing beam 8. The winding device is provided with a separable hollow body 38 (FIG. 3) embracing the magnetic circuit core 5 being bandaged at that portion thereof, and which is disposed between the adjacent pairs of the supports 3 and shoes 29.

A spool 39 with a tape 40 of a bandaging material 11 is mounted in the body 38, the spool 39 being provided with drive means adapted to rotate the spool 39 around the portion of the core 5 being bandaged by winding the tape 40 therearound. Upon winding, the tape 40 is paid off the spool 39 so as to form a multilayer bandage 11.

The separable body 38 has a line of separation extending along a vertical plane extending through the axis of the pressing beam 8 and dividing the body into two symmetrical parts 38a and 38b. The parts are suspended by means of brackets 41a and 41b, to sliders 42a and 42b which are mounted on a guide 43 of the pressing beam, the sliders being movable so as to move them apart (or together) in a plane extending normal to the axis of the beam 8 in order to thereby effect the movement apart (or together) of the parts 38a and 38b of the body 38. Accordingly, the sliders 42a and 42b are interconnected by means of a screw 44 having right=hand and left-hand threads. This screw is driven by a handle 45 of an interlocked drive 46 which is also adapted to ensure the movement of the winding device 10 on the guides 43 of the pressing beam 8 along the longitudinal axis thereof.

The drive 46 is provided with a toothed rack 47 which is secured lengthwise to the pressing beam 8, and which is meshed with a gear 48 mounted at one end of the horizontal shaft 49. Loosely fitted onto the other end of the shaft 49, and supported in a bracket 50, is a gear 51 with including a part of a cam clutch 52a, while the end of the shaft 49 is provided with a squareshaped portion mounting a handle 45 with a second part 52b of the clutch.

The gear 51 is engaged with a gear 54 via an intermediate gear 53, the gear 54 being secured to the end of the screw 44 interconnecting the sliders 42a and 4219'. Thus, when in its extreme right position (which is shown in FIG. 4), the handle 45 (secured to the squareshaped end of the shaft 49) serves to rotate this shaft 43 for rolling the gear 48 along the toothed rack and to thereby move the winding device 10 along the axis of the pressing beam 8.

Drive means for rotating the spool with the tape 40 of the bandaging material comprise a dirven gear 55 which is accommodated in the body 38 of the winding device 10 and made in the form of two half-rings 55a and 5512, an axle adapted to receive the spool 39, and a system of brake rollers 56 and guide rollers 57 which are secured to the surface of one of the half-rings. The gear 55 is in constant engagement with a pinion 58 secured to a shaft of a chain drive sprocket 59, the latter of which is rotated by the shaft of a reduction gear 60 mounted on the slider 42a, which in turn is driven by an electric motor 61.

The motor 61 is attached to a guide 62 secured to the beam 8, and is capable of moving along the guide upon bringing the parts 38a and 38b of the body together in conjunction with the half-rings 55a and 55b of the gear 55.

The assembly of the magnetic circuit on the abovedescribed stand comprises the following sequence of steps.

In its initial position, the base 1 of the stand is placed horizontally with the pressing beam'8 together with the bars 7, and with the winding device 10 being removed from the table 2. The parts 38a and 38b of the body 38 are separated from the associated brackets 41a and 41b.

The first assembling step comprises stacking together in stacks 25 the laminations cut from electrical sheet steel. This operation consists of in stacking the laminations 25 (in accordance with the lamination pattern beams the magnetic circuit to be assembled) so as to be laid upon the supports 3 and 4 of the assembly table 2, and followed by fixing them in a horizontal plane by means of the stops 24.

The stacks 25 of the laminations which are positioned on the supports 3 along the bemas 20 of the assembly table 2 form, after bandaging thereof, the cores 5 of the magnetic circuit 11, while the stacks 25 placed onto the supports 4 across the beams 20 define the magnetic circuit yokes 6'which interconnect the cores After placing the stacks 25 on the supports 3 and 4 of the assembly table 2, the removable pressing beam 8 is positioned above one of the longituidinal beams 20 with the aid of a bridge crane (not shown). In order to do this, the lower ends of the vertical bars 7 supporting the pressing beam are inserted into the associated sockets provided on the ends of the beam 20 of the table 2, and are secured in these sockets by means of the wedges 28. Thereupon, the drives 9 are energized so as to shift the pressing beam 8 along the guide bars 7 in the direction of the assembling table 2 for pressing the stacks 25 which are placed on the beam 20 of the table 2. In this case, rotation of the electrical motors 31 is transmitted to the reduction worm gear 32 which in turn rotates the nuts 37, and in which the nuts, while synchronously moving down, pull the pressing beam 8 down through the reduction gears. The pressure of the pressing beam 8 is transmitted to the stacks 25 of the core 5 via the pressing shoes 29.

After the pressing of the core 5, the pressing force is not relieved from the core, and the bandages l1 interconnecting the stacks 25 are wound around the portions of the cores 5 which are disposed between the pairs of the supports 3 and the associated shoes 29.

Prior to the winding of the bandages 11, the winding device is shifted along the axis of the pressing bar 8 and positioned above the first portion of the core 5 being bandaged.

The handle 45 of the mechanism 46 is shifted along the shaft 49 to the extreme position, in which rotation of the handle is transmitted to the shaft 49, and from the latter to the gear 48 rolling along the tooth rack 49, thereby shifting the winding device 10 through the required distance along the axis of the pressing beam 8.

and 52b of the clutch are engaged, and rotation of the After that, the leading end of the tape 40, which is wound on the spool 39 mounted in the body 38 on the axle, is pulled through the system of the brake rollers 56 and guide rollers 57 and is secured to the core 5.

Thereupon, the electric motor 61 of the drive is actuated so as to turn the spool 39 around the core 5. The

rotation of the shaft of the electric motor 61 imparted to the reduction gear 60, the chain drive 59 and the gear 58, is transmitted to the gear 55 which is secured to the axis 56 mounting the spool 39, whereby the tape 40 of the bandaging material is paid off the axis of the spool 39 and wound around the core to thereby form the bandage 11.

After winding a predetermined number of turns of the bandage 11, the electric motor is deenergizedupon actuation of a pulse counter (not shown), the tape 40 is cut off, and the end of the tape is fixed to the penultimate turn of the bandage. 1

Thereupon, the line of separation of the body 38 is aligned with that of the gear 55 of the winding device 10, and the parts 38a and 38b of the body 38, together with the half-rings 55a and 55b of the gear 55, are moved apart a distance exceeding the width C of the pressing shoes 29 and supports 3 (as it is shown in FIG. 4) in order to pass clear of the latter upon movement of the winding device along the axis of the pressing beam 8 towards the next portion of the core 5 to be bandaged, whereupon the parts 38a and 38b of the body 38 are again brought together, and the bandaging cycle is repeated.

Movement apart or together of the parts-38a and 38b of the body 38 of the winding device 10 and shifting thereof along the axis of the pressing beam 8 is carried out by means of the handle 45 of the drive 46, as described above.

After winding the required number of bandages 11 around the core 5, the parts 38a and. 38b of the body 38 of the winding device 10 are moved apart and removed from the brackets 41a and 41b. The pressing force on the core 5 is then relieved (the raising of the pressing beam is a process reverse to that of the lowering thereof) and the lower ends of the guide bars 7 are unclamped, following the positioning of the pressing beam 8 over the next longitudinal beam of the assembly table 2. Thereafter all the above listed operations are repeated in the same order.

After all of the cores 5 of the magnetic circuit have been bandaged, the pressing beam is removed together with the bars 7, the magnetic circuit is supported by means of the abutment screws 27, and the base 1 of the stand 15 is turned on the hook 64 (FIG. 1) (with the,

aid of a bridge crane), together with the assembled magnetic core. into a substantially vertical position. As the base 1 is turned from the horizontal into the vertical position, the fingers 15 provided in the sledges 12 successively come into engagement with the toothed rack 16 of the plate 13, thereby preventing the sledges from shifting with respect to the plate 13.

in its vertical position the base 1 is fixed by means of the brackets 17 which are placed against the stops 18 provided on the plate 13. I

The assembled magnetic circuit is removed (with the aid of a bridge crane) from the stand in a vertically oriented position, while the base 1 together with the table 2 is returned to the initial horizontal position with the handle 19 having been previouslyturned into the position of effecting the disengagement of the brackets 17 from the stops 18. Thereafter the stand is ready for as-' sembly of the next magnetic circuit.

The stand for assembling the magnetic circuits according to the present invention allows for increasing labor efficiency and for improving quality of the magnetic circuits of power transformers.

While a preferred embodiment of the present invention has been shown and described herein, other equivalent embodiments of the winding device and the stand proper are possible within the scope of the invention as definedby the appended claims.

What is'claimed is:

1. A stand for assembling magnetic circuits of power transformers comprising: a turnable base; an assembly table with supports mounting stacks, of laminations forming elements of the magnetic circuit to be assembled; a removable pressing beam positioned above said table on guide bars and provided with shoes attached to the lower end thereof over each of said supports of the tabla-respectively, so that upon shifting of said beam in the direction of said table the shoes transmit a pressing force to the elements of the magnetic circuit to be assembled which are placed on said table supports to compress them; means to shift said beam along said barsya winding device mounted on said beam and provided with a separable body adapted to embrace the elements of the magnetic circuit to be bandaged stepby-step at the portions thereof between the shoes of said beam; means to shift said device along the axis of said beam; a separable ring accommodated on the body of said winding device and mounting an axle adapted to receive a spool with a tape of bandaging material; means to rotate said ring together with said spool around said element to be bandaged for winding bandaging material thereupon.

2. A stand as claimed in claim 1, wherein thebody of said winding device and the ring accommodated therein with the axle for receiving the spool with bandaging material are separated along a vertical plane extending through an axis of said pressing beam dividing them into two symmetrical parts mounted so as'to be brought apart or together in a plane normal to the axis of the pressing beam.

3. A stand as claimed in claim 2, wherein in order to ensure the bringing said parts of the body along with said parts of the ring apart andtogether, said parts of the housing are suspended to the respective sliders which are mounted on the pressing beam guides and are interconnected by means a screw drive interlocked with means for shifting said winding device along the pressing beam axis. v

4. A stand as claimed in claim 2, wherein said ring with the axle receiving the spool is formed as a gear, a second gear being in meshed engagement therewith, and an electric motor driving said second gear through a chain drive and a reduction gear, said electric motor being mounted on said pressing beam. 

1. A stand for assembling magnetic circuits of power transformers comprising: a turnable base; an assembly table with supports mounting stacks of laminations forming elements of the magnetic circuit to be assembled; a removable pressing beam positioned above said table on guide bars and provided with shoes attached to the lower end thereof over each of said supports of the table, respectively, so that upon shifting of said beam in the direction of said table the shoes transmit a pressing force to the elements of the magnetic circuit to be assembled which are placed on said table supports to compress them; means to shift said beam along said bars; a winding device mounted on said beam and provided with a separable body adapted to embrace the elements of the magnetic circuit to be bandaged step-by-step at the portions thereof between the shoes of said beam; means to shift said device along the axis of said beam; a separable ring accommodated on the body of said winding device and mounting an axle adapted to receive a spool with a tape of bandaging material; means to rotate said ring together with said spool around said element to be bandaged for winding bandaging material thereupon.
 2. A stand as claimed in claim 1, wherein the body of said winding device and the ring accommodated therein with the axle for receiving the spool with bandaging material are separated along a vertical plane extending through an axis of said pressing beam dividing them into two symmetrical parts mounted so as to be brought apart or together in a plane normal to the axis of the pressing beam.
 3. A stand as claimed in claim 2, wherein in order to ensure the bringing said parts of the body along with said parts of the ring apart and together, said parts of the housing are suspended to the respective sliders which are mounted on the pressing beam guides and are interconnected by means a screw drive interlocked with means for shifting said winding device along the pressing beam axis.
 4. A stand as claimed in claim 2, wherein said ring with the axle receiving the spool is formed as a gear, a second gear being in meshed engagement therewith, and an electric motor driving said second gear through a chain drive and a reduction gear, said electric motor being mounted on said pressing beam. 